Browsing by Author "Sharath, P.C."

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Effect of Mechanical properties on Multi Axially Forged LM4 Aluminium Alloy
(Elsevier Ltd, 2020) Sajjan, S.S.; Kulkarni, M.V.; Ramesh, S.; Sharath, P.C.; Kumar, V.; Rajole, S.
Commercially available LM4 Aluminum alloy was subjected through Severe Plastic Deformation (SPD) method by Multi-Axial Forging Process (MAF) in ambient temperature. In this process, the material was processed successfully up to 5 Passes and mechanical properties such as tensile strength, compression strength and hardness of the as received and processed samples at ambient temperature were evaluated. The MAF processed sample result showed that the ultimate strength, percentage elongation and compression strength improved by 55 MPa, 3.75% and 162 MPa respectively as compared with the unprocessed sample. Hardness also increased with the increase in the number of passes. In the case of microstructure, grain size reduced from 110 Î¼m to 8 Î¼m after subjecting the sample to MAF. Fractography explains the nature of the fracture from received to processed samples by decreasing the size of the dimple and the type of fracture observed was ductile in nature. Improvement in strength and hardness of processed samples was observed due to the grain refinement and high amount of density dislocation in the material during MAF. Â© 2018 Elsevier Ltd.
Effect of multi directional forging on impression creep behavior of Zn-24Al-2Cu alloy
(2018) Sharath, P.C.; Rajendra, Udupa, K.; Kumar, G.V.P.
Multi directional forging (MDF) of Zn-24Al-2Cu alloy were carried at 100�C and 200�C with total equivalent strain of 0.6 and 1.2 respectively. The average grain size was reduced from 30 to 1 ?m after MDF processing. Impression creep behavior of MDF processed samples was studied at 2 kg and 2.5 kg load with temperatures 30, 50, 100 and 150�C. Microstructural characterizations were carried out using optical microscope, transmission electron microscope and X-Ray diffractometer. Steady state creep rate values were recorded in the range of 1.2x10-5 to 5.2x10-7. The four phase transformation occurred in the structure after MDF process and during the impression creep test. Initial stress exponent (n) values are in the range of 2.5 to greater than 5. High values of 'n' showed due to the existence of threshold stress. The true activation energy values calculated are in the range of 22-129 kJ/mol. Changes in creep properties of MDF processed samples seem to be more sensitive to change in temperature compared to microstructural differences. Lattice diffusion controlled by dislocation climb is the dominant creep mechanism. � 2018 Elsevier Ltd. All rights reserved.
Effect of multi directional forging on impression creep behavior of Zn-24Al-2Cu alloy
(Elsevier Ltd, 2018) Sharath, P.C.; Rajendra Udupa, K.; Preetham Kumar, G.V.
Multi directional forging (MDF) of Zn-24Al-2Cu alloy were carried at 100Â°C and 200Â°C with total equivalent strain of 0.6 and 1.2 respectively. The average grain size was reduced from 30 to 1 Î¼m after MDF processing. Impression creep behavior of MDF processed samples was studied at 2 kg and 2.5 kg load with temperatures 30, 50, 100 and 150Â°C. Microstructural characterizations were carried out using optical microscope, transmission electron microscope and X-Ray diffractometer. Steady state creep rate values were recorded in the range of 1.2x10-5 to 5.2x10-7. The four phase transformation occurred in the structure after MDF process and during the impression creep test. Initial stress exponent (n) values are in the range of 2.5 to greater than 5. High values of 'n' showed due to the existence of threshold stress. The true activation energy values calculated are in the range of 22-129 kJ/mol. Changes in creep properties of MDF processed samples seem to be more sensitive to change in temperature compared to microstructural differences. Lattice diffusion controlled by dislocation climb is the dominant creep mechanism. Â© 2018 Elsevier Ltd. All rights reserved.
Effect of Multi Directional Forging on the Microstructure and Mechanical Properties of Zn-24 wt% Al-2 wt% Cu Alloy
(Springer India sanjiv.goswami@springer.co.in, 2017) Sharath, P.C.; Udupa, K.R.; Preetham Kumar, G.V.
Multi directional forging is an important process for producing fine grains in bulk materials by means of severe plastic deformation. Zn-Al alloy is used for making sleeves of plain bearings, but the presence of porosity degrades its usage in industrial application. In the present investigation, multi directional forging of Zn-24Al-2Cu alloy was carried out at 100 and 200 °C up to total strain of 0.6 and 1.2 respectively. Mechanical properties and microstructural characterization were carried out on the processed material. It was inferred that processing at 100 °C up to three passes increased ultimate tensile strength from 185 to 267 MPa with ductility of 14 %. The average grain size was reduced from 30 to 2 µm. In the case of samples processed at 200 °C up to six passes, the average grain size was reduced to 1 µm. The ultimate tensile strength increased to 276 MPa and ductility significantly improved to 21 %. The strength of the processed material increased due to strain hardening and grain refinement. Uniform distribution of various dispersed phases contributed to the enhancement of ductility during multi directional forging at 200 °C. Analysis of the fractured surface of the tensile samples revealed highly ductile nature of the fracture. © 2016, The Indian Institute of Metals - IIM.
Effect of multidirectional forging on grain structure and mechanical properties of hypereutectic Al–20%Si alloys with added refiners and modifiers; Effet du forgeage multidirectionnel sur la structure des grains et les propriétés mécaniques des alliages hypereutectiques Al-20%Si avec des agents d’affinage et modificateurs ajoutés
(Taylor and Francis Ltd., 2025) Nagaraj, C.; Dutt, K.M.; Manjunath, G.K.; Sharath, P.C.; Sollapur, S.B.; B R, B.K.; Kumar, B.; Arunkumar, D.T.
The present work is focused on the multidirectional forging (MDF) of Al–20 wt-% Si alloys with the addition of refiners and modifiers. The MDF process was performed at 200°C with a cumulative strain of 0.63. Microstructural characterization and mechanical performance were evaluated on the Al–20Si, Al–20Si–4.5Cu, Al–20Si–4.5Cu–1(Al–Ti–B), Al–20Si–4.5Cu–1(Al–Ti–B)–10(Al–Sr). The microstructure analysis revealed significant changes in the eutectic and primary phase refinement. The micro-Vickers hardness confirmed that the MDF process resulted in increased hardness (125 ± 1.9 VHN) compared to the homogenized samples (96 ± 2.7 VHN). Tensile test results showed that with the accumulation of strain, ultimate tensile strength increased to 435 MPa from 302 MPa with reduction in the percentage of elongation from 7.8 to 5.6. The grains were more uniformly distributed with addition of modifiers, and refiners further reduced the nucleation number of eutectic grains. The wear study demonstrated that the wear resistance is more in the Al–Si-Cu-Sr sample due to the increased level of hardness. The combination of multidirectional forging techniques with judicious incorporation of refiners and modifiers engenders a synergistic enhancement of microstructural integrity, hardness profiles, and wear-resistant properties in hypereutectic Al-20Si alloys. © 2024 Canadian Institute of Mining, Metallurgy and Petroleum.
Evaluation of microstructure and mechanical properties of multi axial forged lm2 aluminum alloy
(2019) Sajjan, S.S.; Kulkarni, M.V.; Ramesh, S.; Sharath, P.C.; Sangamesh, R.; Kumar, A.; Rajesh, R.
Light metal Al alloys are presently used in aerospace and industrial applications. Hence, in the present study choice of material will be LM2 aluminum alloy and processed by multi-axial forging (MAF) technique at ambient temperature for different number of passes with an equivalent strain of 0.18, 0.36 and 0.54. Microstructural analysis was carried out on unprocessed and processed samples with scanning electron microscopy (SEM). As the number of MAF pass increases the average grain size was reduced because of plastic deformation by plane strain condition. Mechanical properties like Vickers hardness (VHN), tensile and compression test were carried out. Ultimate tensile strength (UTS) was increased after each pass of MAF due to strain hardening effect. After 3 MAF passes the compression strength was reached to maximum of 495 MPa as compared to as received sample 315 MPa and hardness, increased to 81 VHN as compared to 55 VHN for the received samples. The fractography analysis was explained using SEM images. As the number of passes increases dimple size reduces as compared to as received samples and which will be revealing the ductile mode of fracture. � 2019 Trans Tech Publications Ltd, Switzerland.
Evaluation of microstructure and mechanical properties of multi axial forged lm2 aluminum alloy
(Trans Tech Publications Ltd ttp@transtec.ch, 2019) Sajjan, S.S.; Kulkarni, M.V.; Ramesh, S.; Sharath, P.C.; Sangamesh, R.; Kumar, A.; Rajesh, R.
Light metal Al alloys are presently used in aerospace and industrial applications. Hence, in the present study choice of material will be LM2 aluminum alloy and processed by multi-axial forging (MAF) technique at ambient temperature for different number of passes with an equivalent strain of 0.18, 0.36 and 0.54. Microstructural analysis was carried out on unprocessed and processed samples with scanning electron microscopy (SEM). As the number of MAF pass increases the average grain size was reduced because of plastic deformation by plane strain condition. Mechanical properties like Vickers hardness (VHN), tensile and compression test were carried out. Ultimate tensile strength (UTS) was increased after each pass of MAF due to strain hardening effect. After 3 MAF passes the compression strength was reached to maximum of 495 MPa as compared to as received sample 315 MPa and hardness, increased to 81 VHN as compared to 55 VHN for the received samples. The fractography analysis was explained using SEM images. As the number of passes increases dimple size reduces as compared to as received samples and which will be revealing the ductile mode of fracture. Â© 2019 Trans Tech Publications Ltd, Switzerland.
Mechanical and Microstructural Properties of Multi-Axially Forged LM6 Aluminium Alloy
(Pleiades journals, 2019) Sajjan, S.S.; Kulkarni, M.V.; Ramesh, S.; Sharath, P.C.; Rajesh, R.; Kumar, V.
In the present investigation, commercially available light metal aluminium LM6 alloy was processed by Multi-axial forging (MAF) at ambient temperature. MAF was carried out to an equivalent strain in 0.83, 1.66 and 2.4 i.e., 6 passes, 12 passes and 18 passes, respectively. The mechanical properties like tensile test, compression test, hardness and microstructural characterization were studied in processed and unprocessed samples. Ultimate tensile strength (UTS) and ductility improved from 137 to 185 MPa and 3 to 6.2% for as-received to processed samples, respectively. After 18 passes of MAF, the compression strength (CS) has improved from 342 to 530 MPa. Hardness increased as the number of forging passes increases as compared to unprocessed samples. Optical microscopy images were used to study microstructure observations, the average grain size is reduced from 60 to 2 μm for as-received to processed samples, respectively. Strength and hardness increased because of the grain refinement for the processed samples and the introduction of the high amount of dislocation density into the material during the MAF process. Fracture study was conducted by utilizing scanning electron microscopy, dimples on tensile fracture surfaces revealed that ductile mode of fracture. © 2019, Springer Nature Singapore Pte Ltd.